This invention relates to a heating appliance having a home menu or user program function such that preset heating data comprising combinations of heating time, heat output, heating temperature, etc. are recalled by one touch and further comprising an electrically rewritable nonvolatile memory for storing said heating data.
There is already available a heating appliance having the so-called user program function such that preset heating data comprising combinations of heating time, heat output, heating temperature, etc. are recalled by one touch. The commercial models of this type available today may be classed into the following three major categories.
In a first system including a RAM, for example a 1-chip microcomputer (hereinafter briefly, mycon), as a main control means, heating data are stored in the built-in RAM of the mycon. While this is a simple and inexpensive system, the heating data are destroyed by a current failure.
A second system, developed to overcome the above disadvantage, is provided with a battery for backing up the memory. Although this enables backing up of the memory in a current failure, the useful life and reliability of the battery becomes a problem. Especially in the case of a heating appliance, where the ambient temperature of the mechanical compartment is fairly high, discharge of the battery is accelerated. Moreover, the system is scaled up of necessity due to the provision of a current failure detection circuit, a battery power supply switching circuit, etc., with an inevitable decrease in reliability and, of course, an addition to the manufacturing cost.
In a third system, heating data are not stored in a memory but preset in switches or volumes. Here, the home menu is stored by mechanical means so that the function is not affected by current failures. This system is advantageous from reliability point of view, too.
However, the disadvantage of the last-mentioned system is that it is not easy to operate or manipulate. Thus, there must be provided a switch or volume for each of the different menus so that the control panel is complicated. Moreover, it is procedurally difficult to preset a sequential heating pattern comprising a combination of dissimilar heat outputs or/and heating times.